位于8p22 - 23的一个新的扩增子导致食管腺癌中组织蛋白酶B的过表达。

A novel amplicon at 8p22-23 results in overexpression of cathepsin B in esophageal adenocarcinoma.

作者信息

Hughes S J, Glover T W, Zhu X X, Kuick R, Thoraval D, Orringer M B, Beer D G, Hanash S

机构信息

Department of Surgery, Section of Thoracic Surgery, University of Michigan Medical School, Ann Arbor, MI 48109, USA.

出版信息

Proc Natl Acad Sci U S A. 1998 Oct 13;95(21):12410-5. doi: 10.1073/pnas.95.21.12410.

DOI:10.1073/pnas.95.21.12410

PMID:9770500

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC22845/

Abstract

Cathepsin B (CTSB) is overexpressed in tumors of the lung, prostate, colon, breast, and stomach. However, evidence of primary genomic alterations in the CTSB gene during tumor initiation or progression has been lacking. We have found a novel amplicon at 8p22-23 that results in CTSB overexpression in esophageal adenocarcinoma. Amplified genomic NotI-HinfI fragments were identified by two-dimensional DNA electrophoresis. Two amplified fragments (D4 and D5) were cloned and yielded unique sequences. Using bacterial artificial chromosome clones containing either D4 or D5, fluorescent in situ hybridization defined a single region of amplification involving chromosome bands 8p22-23. We investigated the candidate cancer-related gene CTSB, and potential coamplified genes from this region including farnesyl-diphosphate farnesyltransferase (FDFT1), arylamine N-acetyltransferase (NAT-1), lipoprotein lipase (LPL), and an uncharacterized expressed sequence tag (D8S503). Southern blot analysis of 66 esophageal adenocarcinomas demonstrated only CTSB and FDFT1 were consistently amplified in eight (12.1%) of the tumors. Neither NAT-1 nor LPL were amplified. Northern blot analysis showed overexpression of CTSB and FDFT1 mRNA in all six of the amplified esophageal adenocarcinomas analyzed. CTSB mRNA overexpression also was present in two of six nonamplified tumors analyzed. However, FDFT1 mRNA overexpression without amplification was not observed. Western blot analysis confirmed CTSB protein overexpression in tumor specimens with CTSB mRNA overexpression compared with either normal controls or tumors without mRNA overexpression. Abundant extracellular expression of CTSB protein was found in 29 of 40 (72. 5%) of esophageal adenocarcinoma specimens by using immunohistochemical analysis. The finding of an amplicon at 8p22-23 resulting in CTSB gene amplification and overexpression supports an important role for CTSB in esophageal adenocarcinoma and possibly in other tumors.

摘要

组织蛋白酶B（CTSB）在肺癌、前列腺癌、结肠癌、乳腺癌和胃癌中均有过表达。然而，在肿瘤发生或进展过程中，CTSB基因原发性基因组改变的证据一直缺乏。我们在8p22 - 23发现了一个新的扩增子，它导致食管腺癌中CTSB过表达。通过二维DNA电泳鉴定出扩增的基因组NotI - HinfI片段。克隆了两个扩增片段（D4和D5）并获得了独特序列。使用包含D4或D5的细菌人工染色体克隆，荧光原位杂交确定了一个单一的扩增区域，涉及染色体带8p22 - 23。我们研究了候选癌症相关基因CTSB以及该区域潜在的共扩增基因，包括法尼基二磷酸法尼基转移酶（FDFT1）、芳胺N - 乙酰转移酶（NAT - 1）、脂蛋白脂肪酶（LPL）和一个未鉴定的表达序列标签（D8S503）。对66例食管腺癌进行Southern印迹分析表明，仅CTSB和FDFT1在8例（12.1%）肿瘤中持续扩增。NAT - 1和LPL均未扩增。Northern印迹分析显示，在所有分析的6例扩增食管腺癌中，CTSB和FDFT1 mRNA均过表达。在分析的6例未扩增肿瘤中，也有2例存在CTSB mRNA过表达。然而，未观察到无扩增的FDFT1 mRNA过表达。Western印迹分析证实，与正常对照或无mRNA过表达的肿瘤相比，CTSB mRNA过表达的肿瘤标本中CTSB蛋白过表达。通过免疫组织化学分析，在40例食管腺癌标本中的29例（72.5%）发现了丰富的细胞外CTSB蛋白表达。在8p22 - 23发现导致CTSB基因扩增和过表达的扩增子，这一发现支持了CTSB在食管腺癌以及可能在其他肿瘤中发挥重要作用。